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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * S/390 debug facility
4 *
5 * Copyright IBM Corp. 1999, 2020
6 *
7 * Author(s): Michael Holzheu (holzheu@de.ibm.com),
8 * Holger Smolinski (Holger.Smolinski@de.ibm.com)
9 *
10 * Bugreports to: <Linux390@de.ibm.com>
11 */
12
13#define KMSG_COMPONENT "s390dbf"
14#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16#include <linux/stddef.h>
17#include <linux/kernel.h>
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/ctype.h>
21#include <linux/string.h>
22#include <linux/sysctl.h>
23#include <linux/uaccess.h>
24#include <linux/export.h>
25#include <linux/init.h>
26#include <linux/fs.h>
27#include <linux/minmax.h>
28#include <linux/debugfs.h>
29
30#include <asm/debug.h>
31
32#define DEBUG_PROLOG_ENTRY -1
33
34#define ALL_AREAS 0 /* copy all debug areas */
35#define NO_AREAS 1 /* copy no debug areas */
36
37/* typedefs */
38
39typedef struct file_private_info {
40 loff_t offset; /* offset of last read in file */
41 int act_area; /* number of last formated area */
42 int act_page; /* act page in given area */
43 int act_entry; /* last formated entry (offset */
44 /* relative to beginning of last */
45 /* formated page) */
46 size_t act_entry_offset; /* up to this offset we copied */
47 /* in last read the last formated */
48 /* entry to userland */
49 char temp_buf[2048]; /* buffer for output */
50 debug_info_t *debug_info_org; /* original debug information */
51 debug_info_t *debug_info_snap; /* snapshot of debug information */
52 struct debug_view *view; /* used view of debug info */
53} file_private_info_t;
54
55typedef struct {
56 char *string;
57 /*
58 * This assumes that all args are converted into longs
59 * on L/390 this is the case for all types of parameter
60 * except of floats, and long long (32 bit)
61 *
62 */
63 long args[0];
64} debug_sprintf_entry_t;
65
66/* internal function prototyes */
67
68static int debug_init(void);
69static ssize_t debug_output(struct file *file, char __user *user_buf,
70 size_t user_len, loff_t *offset);
71static ssize_t debug_input(struct file *file, const char __user *user_buf,
72 size_t user_len, loff_t *offset);
73static int debug_open(struct inode *inode, struct file *file);
74static int debug_close(struct inode *inode, struct file *file);
75static debug_info_t *debug_info_create(const char *name, int pages_per_area,
76 int nr_areas, int buf_size, umode_t mode);
77static void debug_info_get(debug_info_t *);
78static void debug_info_put(debug_info_t *);
79static int debug_prolog_level_fn(debug_info_t *id,
80 struct debug_view *view, char *out_buf);
81static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
82 struct file *file, const char __user *user_buf,
83 size_t user_buf_size, loff_t *offset);
84static int debug_prolog_pages_fn(debug_info_t *id,
85 struct debug_view *view, char *out_buf);
86static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
87 struct file *file, const char __user *user_buf,
88 size_t user_buf_size, loff_t *offset);
89static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
90 struct file *file, const char __user *user_buf,
91 size_t user_buf_size, loff_t *offset);
92static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
93 char *out_buf, const char *in_buf);
94static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
95 char *out_buf, const char *inbuf);
96static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
97static void debug_events_append(debug_info_t *dest, debug_info_t *src);
98
99/* globals */
100
101struct debug_view debug_hex_ascii_view = {
102 "hex_ascii",
103 NULL,
104 &debug_dflt_header_fn,
105 &debug_hex_ascii_format_fn,
106 NULL,
107 NULL
108};
109EXPORT_SYMBOL(debug_hex_ascii_view);
110
111static struct debug_view debug_level_view = {
112 "level",
113 &debug_prolog_level_fn,
114 NULL,
115 NULL,
116 &debug_input_level_fn,
117 NULL
118};
119
120static struct debug_view debug_pages_view = {
121 "pages",
122 &debug_prolog_pages_fn,
123 NULL,
124 NULL,
125 &debug_input_pages_fn,
126 NULL
127};
128
129static struct debug_view debug_flush_view = {
130 "flush",
131 NULL,
132 NULL,
133 NULL,
134 &debug_input_flush_fn,
135 NULL
136};
137
138struct debug_view debug_sprintf_view = {
139 "sprintf",
140 NULL,
141 &debug_dflt_header_fn,
142 &debug_sprintf_format_fn,
143 NULL,
144 NULL
145};
146EXPORT_SYMBOL(debug_sprintf_view);
147
148/* used by dump analysis tools to determine version of debug feature */
149static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
150
151/* static globals */
152
153static debug_info_t *debug_area_first;
154static debug_info_t *debug_area_last;
155static DEFINE_MUTEX(debug_mutex);
156
157static int initialized;
158static int debug_critical;
159
160static const struct file_operations debug_file_ops = {
161 .owner = THIS_MODULE,
162 .read = debug_output,
163 .write = debug_input,
164 .open = debug_open,
165 .release = debug_close,
166 .llseek = no_llseek,
167};
168
169static struct dentry *debug_debugfs_root_entry;
170
171/* functions */
172
173/*
174 * debug_areas_alloc
175 * - Debug areas are implemented as a threedimensonal array:
176 * areas[areanumber][pagenumber][pageoffset]
177 */
178
179static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
180{
181 debug_entry_t ***areas;
182 int i, j;
183
184 areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
185 if (!areas)
186 goto fail_malloc_areas;
187 for (i = 0; i < nr_areas; i++) {
188 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
189 areas[i] = kmalloc_array(pages_per_area,
190 sizeof(debug_entry_t *),
191 GFP_KERNEL | __GFP_NOWARN);
192 if (!areas[i])
193 goto fail_malloc_areas2;
194 for (j = 0; j < pages_per_area; j++) {
195 areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
196 if (!areas[i][j]) {
197 for (j--; j >= 0 ; j--)
198 kfree(areas[i][j]);
199 kfree(areas[i]);
200 goto fail_malloc_areas2;
201 }
202 }
203 }
204 return areas;
205
206fail_malloc_areas2:
207 for (i--; i >= 0; i--) {
208 for (j = 0; j < pages_per_area; j++)
209 kfree(areas[i][j]);
210 kfree(areas[i]);
211 }
212 kfree(areas);
213fail_malloc_areas:
214 return NULL;
215}
216
217/*
218 * debug_info_alloc
219 * - alloc new debug-info
220 */
221static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
222 int nr_areas, int buf_size, int level,
223 int mode)
224{
225 debug_info_t *rc;
226
227 /* alloc everything */
228 rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
229 if (!rc)
230 goto fail_malloc_rc;
231 rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
232 if (!rc->active_entries)
233 goto fail_malloc_active_entries;
234 rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
235 if (!rc->active_pages)
236 goto fail_malloc_active_pages;
237 if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
238 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
239 if (!rc->areas)
240 goto fail_malloc_areas;
241 } else {
242 rc->areas = NULL;
243 }
244
245 /* initialize members */
246 spin_lock_init(&rc->lock);
247 rc->pages_per_area = pages_per_area;
248 rc->nr_areas = nr_areas;
249 rc->active_area = 0;
250 rc->level = level;
251 rc->buf_size = buf_size;
252 rc->entry_size = sizeof(debug_entry_t) + buf_size;
253 strscpy(rc->name, name, sizeof(rc->name));
254 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
255 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
256 refcount_set(&(rc->ref_count), 0);
257
258 return rc;
259
260fail_malloc_areas:
261 kfree(rc->active_pages);
262fail_malloc_active_pages:
263 kfree(rc->active_entries);
264fail_malloc_active_entries:
265 kfree(rc);
266fail_malloc_rc:
267 return NULL;
268}
269
270/*
271 * debug_areas_free
272 * - free all debug areas
273 */
274static void debug_areas_free(debug_info_t *db_info)
275{
276 int i, j;
277
278 if (!db_info->areas)
279 return;
280 for (i = 0; i < db_info->nr_areas; i++) {
281 for (j = 0; j < db_info->pages_per_area; j++)
282 kfree(db_info->areas[i][j]);
283 kfree(db_info->areas[i]);
284 }
285 kfree(db_info->areas);
286 db_info->areas = NULL;
287}
288
289/*
290 * debug_info_free
291 * - free memory debug-info
292 */
293static void debug_info_free(debug_info_t *db_info)
294{
295 debug_areas_free(db_info);
296 kfree(db_info->active_entries);
297 kfree(db_info->active_pages);
298 kfree(db_info);
299}
300
301/*
302 * debug_info_create
303 * - create new debug-info
304 */
305
306static debug_info_t *debug_info_create(const char *name, int pages_per_area,
307 int nr_areas, int buf_size, umode_t mode)
308{
309 debug_info_t *rc;
310
311 rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
312 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
313 if (!rc)
314 goto out;
315
316 rc->mode = mode & ~S_IFMT;
317 refcount_set(&rc->ref_count, 1);
318out:
319 return rc;
320}
321
322/*
323 * debug_info_copy
324 * - copy debug-info
325 */
326static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
327{
328 unsigned long flags;
329 debug_info_t *rc;
330 int i, j;
331
332 /* get a consistent copy of the debug areas */
333 do {
334 rc = debug_info_alloc(in->name, in->pages_per_area,
335 in->nr_areas, in->buf_size, in->level, mode);
336 spin_lock_irqsave(&in->lock, flags);
337 if (!rc)
338 goto out;
339 /* has something changed in the meantime ? */
340 if ((rc->pages_per_area == in->pages_per_area) &&
341 (rc->nr_areas == in->nr_areas)) {
342 break;
343 }
344 spin_unlock_irqrestore(&in->lock, flags);
345 debug_info_free(rc);
346 } while (1);
347
348 if (mode == NO_AREAS)
349 goto out;
350
351 for (i = 0; i < in->nr_areas; i++) {
352 for (j = 0; j < in->pages_per_area; j++)
353 memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
354 }
355out:
356 spin_unlock_irqrestore(&in->lock, flags);
357 return rc;
358}
359
360/*
361 * debug_info_get
362 * - increments reference count for debug-info
363 */
364static void debug_info_get(debug_info_t *db_info)
365{
366 if (db_info)
367 refcount_inc(&db_info->ref_count);
368}
369
370/*
371 * debug_info_put:
372 * - decreases reference count for debug-info and frees it if necessary
373 */
374static void debug_info_put(debug_info_t *db_info)
375{
376 if (!db_info)
377 return;
378 if (refcount_dec_and_test(&db_info->ref_count))
379 debug_info_free(db_info);
380}
381
382/*
383 * debug_format_entry:
384 * - format one debug entry and return size of formated data
385 */
386static int debug_format_entry(file_private_info_t *p_info)
387{
388 debug_info_t *id_snap = p_info->debug_info_snap;
389 struct debug_view *view = p_info->view;
390 debug_entry_t *act_entry;
391 size_t len = 0;
392
393 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
394 /* print prolog */
395 if (view->prolog_proc)
396 len += view->prolog_proc(id_snap, view, p_info->temp_buf);
397 goto out;
398 }
399 if (!id_snap->areas) /* this is true, if we have a prolog only view */
400 goto out; /* or if 'pages_per_area' is 0 */
401 act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
402 [p_info->act_page] + p_info->act_entry);
403
404 if (act_entry->clock == 0LL)
405 goto out; /* empty entry */
406 if (view->header_proc)
407 len += view->header_proc(id_snap, view, p_info->act_area,
408 act_entry, p_info->temp_buf + len);
409 if (view->format_proc)
410 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
411 DEBUG_DATA(act_entry));
412out:
413 return len;
414}
415
416/*
417 * debug_next_entry:
418 * - goto next entry in p_info
419 */
420static inline int debug_next_entry(file_private_info_t *p_info)
421{
422 debug_info_t *id;
423
424 id = p_info->debug_info_snap;
425 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
426 p_info->act_entry = 0;
427 p_info->act_page = 0;
428 goto out;
429 }
430 if (!id->areas)
431 return 1;
432 p_info->act_entry += id->entry_size;
433 /* switch to next page, if we reached the end of the page */
434 if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
435 /* next page */
436 p_info->act_entry = 0;
437 p_info->act_page += 1;
438 if ((p_info->act_page % id->pages_per_area) == 0) {
439 /* next area */
440 p_info->act_area++;
441 p_info->act_page = 0;
442 }
443 if (p_info->act_area >= id->nr_areas)
444 return 1;
445 }
446out:
447 return 0;
448}
449
450/*
451 * debug_output:
452 * - called for user read()
453 * - copies formated debug entries to the user buffer
454 */
455static ssize_t debug_output(struct file *file, /* file descriptor */
456 char __user *user_buf, /* user buffer */
457 size_t len, /* length of buffer */
458 loff_t *offset) /* offset in the file */
459{
460 size_t count = 0;
461 size_t entry_offset;
462 file_private_info_t *p_info;
463
464 p_info = (file_private_info_t *) file->private_data;
465 if (*offset != p_info->offset)
466 return -EPIPE;
467 if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
468 return 0;
469 entry_offset = p_info->act_entry_offset;
470 while (count < len) {
471 int formatted_line_residue;
472 int formatted_line_size;
473 int user_buf_residue;
474 size_t copy_size;
475
476 formatted_line_size = debug_format_entry(p_info);
477 formatted_line_residue = formatted_line_size - entry_offset;
478 user_buf_residue = len-count;
479 copy_size = min(user_buf_residue, formatted_line_residue);
480 if (copy_size) {
481 if (copy_to_user(user_buf + count, p_info->temp_buf
482 + entry_offset, copy_size))
483 return -EFAULT;
484 count += copy_size;
485 entry_offset += copy_size;
486 }
487 if (copy_size == formatted_line_residue) {
488 entry_offset = 0;
489 if (debug_next_entry(p_info))
490 goto out;
491 }
492 }
493out:
494 p_info->offset = *offset + count;
495 p_info->act_entry_offset = entry_offset;
496 *offset = p_info->offset;
497 return count;
498}
499
500/*
501 * debug_input:
502 * - called for user write()
503 * - calls input function of view
504 */
505static ssize_t debug_input(struct file *file, const char __user *user_buf,
506 size_t length, loff_t *offset)
507{
508 file_private_info_t *p_info;
509 int rc = 0;
510
511 mutex_lock(&debug_mutex);
512 p_info = ((file_private_info_t *) file->private_data);
513 if (p_info->view->input_proc) {
514 rc = p_info->view->input_proc(p_info->debug_info_org,
515 p_info->view, file, user_buf,
516 length, offset);
517 } else {
518 rc = -EPERM;
519 }
520 mutex_unlock(&debug_mutex);
521 return rc; /* number of input characters */
522}
523
524/*
525 * debug_open:
526 * - called for user open()
527 * - copies formated output to private_data area of the file
528 * handle
529 */
530static int debug_open(struct inode *inode, struct file *file)
531{
532 debug_info_t *debug_info, *debug_info_snapshot;
533 file_private_info_t *p_info;
534 int i, rc = 0;
535
536 mutex_lock(&debug_mutex);
537 debug_info = file_inode(file)->i_private;
538 /* find debug view */
539 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
540 if (!debug_info->views[i])
541 continue;
542 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
543 goto found; /* found view ! */
544 }
545 /* no entry found */
546 rc = -EINVAL;
547 goto out;
548
549found:
550
551 /* Make snapshot of current debug areas to get it consistent. */
552 /* To copy all the areas is only needed, if we have a view which */
553 /* formats the debug areas. */
554
555 if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
556 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
557 else
558 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
559
560 if (!debug_info_snapshot) {
561 rc = -ENOMEM;
562 goto out;
563 }
564 p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
565 if (!p_info) {
566 debug_info_free(debug_info_snapshot);
567 rc = -ENOMEM;
568 goto out;
569 }
570 p_info->offset = 0;
571 p_info->debug_info_snap = debug_info_snapshot;
572 p_info->debug_info_org = debug_info;
573 p_info->view = debug_info->views[i];
574 p_info->act_area = 0;
575 p_info->act_page = 0;
576 p_info->act_entry = DEBUG_PROLOG_ENTRY;
577 p_info->act_entry_offset = 0;
578 file->private_data = p_info;
579 debug_info_get(debug_info);
580 nonseekable_open(inode, file);
581out:
582 mutex_unlock(&debug_mutex);
583 return rc;
584}
585
586/*
587 * debug_close:
588 * - called for user close()
589 * - deletes private_data area of the file handle
590 */
591static int debug_close(struct inode *inode, struct file *file)
592{
593 file_private_info_t *p_info;
594
595 p_info = (file_private_info_t *) file->private_data;
596 if (p_info->debug_info_snap)
597 debug_info_free(p_info->debug_info_snap);
598 debug_info_put(p_info->debug_info_org);
599 kfree(file->private_data);
600 return 0; /* success */
601}
602
603/* Create debugfs entries and add to internal list. */
604static void _debug_register(debug_info_t *id)
605{
606 /* create root directory */
607 id->debugfs_root_entry = debugfs_create_dir(id->name,
608 debug_debugfs_root_entry);
609
610 /* append new element to linked list */
611 if (!debug_area_first) {
612 /* first element in list */
613 debug_area_first = id;
614 id->prev = NULL;
615 } else {
616 /* append element to end of list */
617 debug_area_last->next = id;
618 id->prev = debug_area_last;
619 }
620 debug_area_last = id;
621 id->next = NULL;
622
623 debug_register_view(id, &debug_level_view);
624 debug_register_view(id, &debug_flush_view);
625 debug_register_view(id, &debug_pages_view);
626}
627
628/**
629 * debug_register_mode() - creates and initializes debug area.
630 *
631 * @name: Name of debug log (e.g. used for debugfs entry)
632 * @pages_per_area: Number of pages, which will be allocated per area
633 * @nr_areas: Number of debug areas
634 * @buf_size: Size of data area in each debug entry
635 * @mode: File mode for debugfs files. E.g. S_IRWXUGO
636 * @uid: User ID for debugfs files. Currently only 0 is supported.
637 * @gid: Group ID for debugfs files. Currently only 0 is supported.
638 *
639 * Return:
640 * - Handle for generated debug area
641 * - %NULL if register failed
642 *
643 * Allocates memory for a debug log.
644 * Must not be called within an interrupt handler.
645 */
646debug_info_t *debug_register_mode(const char *name, int pages_per_area,
647 int nr_areas, int buf_size, umode_t mode,
648 uid_t uid, gid_t gid)
649{
650 debug_info_t *rc = NULL;
651
652 /* Since debugfs currently does not support uid/gid other than root, */
653 /* we do not allow gid/uid != 0 until we get support for that. */
654 if ((uid != 0) || (gid != 0))
655 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
656 BUG_ON(!initialized);
657
658 /* create new debug_info */
659 rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
660 if (rc) {
661 mutex_lock(&debug_mutex);
662 _debug_register(rc);
663 mutex_unlock(&debug_mutex);
664 } else {
665 pr_err("Registering debug feature %s failed\n", name);
666 }
667 return rc;
668}
669EXPORT_SYMBOL(debug_register_mode);
670
671/**
672 * debug_register() - creates and initializes debug area with default file mode.
673 *
674 * @name: Name of debug log (e.g. used for debugfs entry)
675 * @pages_per_area: Number of pages, which will be allocated per area
676 * @nr_areas: Number of debug areas
677 * @buf_size: Size of data area in each debug entry
678 *
679 * Return:
680 * - Handle for generated debug area
681 * - %NULL if register failed
682 *
683 * Allocates memory for a debug log.
684 * The debugfs file mode access permissions are read and write for user.
685 * Must not be called within an interrupt handler.
686 */
687debug_info_t *debug_register(const char *name, int pages_per_area,
688 int nr_areas, int buf_size)
689{
690 return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
691 S_IRUSR | S_IWUSR, 0, 0);
692}
693EXPORT_SYMBOL(debug_register);
694
695/**
696 * debug_register_static() - registers a static debug area
697 *
698 * @id: Handle for static debug area
699 * @pages_per_area: Number of pages per area
700 * @nr_areas: Number of debug areas
701 *
702 * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
703 *
704 * Note: This function is called automatically via an initcall generated by
705 * DEFINE_STATIC_DEBUG_INFO.
706 */
707void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
708{
709 unsigned long flags;
710 debug_info_t *copy;
711
712 if (!initialized) {
713 pr_err("Tried to register debug feature %s too early\n",
714 id->name);
715 return;
716 }
717
718 copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
719 id->level, ALL_AREAS);
720 if (!copy) {
721 pr_err("Registering debug feature %s failed\n", id->name);
722
723 /* Clear pointers to prevent tracing into released initdata. */
724 spin_lock_irqsave(&id->lock, flags);
725 id->areas = NULL;
726 id->active_pages = NULL;
727 id->active_entries = NULL;
728 spin_unlock_irqrestore(&id->lock, flags);
729
730 return;
731 }
732
733 /* Replace static trace area with dynamic copy. */
734 spin_lock_irqsave(&id->lock, flags);
735 debug_events_append(copy, id);
736 debug_areas_swap(id, copy);
737 spin_unlock_irqrestore(&id->lock, flags);
738
739 /* Clear pointers to initdata and discard copy. */
740 copy->areas = NULL;
741 copy->active_pages = NULL;
742 copy->active_entries = NULL;
743 debug_info_free(copy);
744
745 mutex_lock(&debug_mutex);
746 _debug_register(id);
747 mutex_unlock(&debug_mutex);
748}
749
750/* Remove debugfs entries and remove from internal list. */
751static void _debug_unregister(debug_info_t *id)
752{
753 int i;
754
755 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
756 if (!id->views[i])
757 continue;
758 debugfs_remove(id->debugfs_entries[i]);
759 }
760 debugfs_remove(id->debugfs_root_entry);
761 if (id == debug_area_first)
762 debug_area_first = id->next;
763 if (id == debug_area_last)
764 debug_area_last = id->prev;
765 if (id->prev)
766 id->prev->next = id->next;
767 if (id->next)
768 id->next->prev = id->prev;
769}
770
771/**
772 * debug_unregister() - give back debug area.
773 *
774 * @id: handle for debug log
775 *
776 * Return:
777 * none
778 */
779void debug_unregister(debug_info_t *id)
780{
781 if (!id)
782 return;
783 mutex_lock(&debug_mutex);
784 _debug_unregister(id);
785 mutex_unlock(&debug_mutex);
786
787 debug_info_put(id);
788}
789EXPORT_SYMBOL(debug_unregister);
790
791/*
792 * debug_set_size:
793 * - set area size (number of pages) and number of areas
794 */
795static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
796{
797 debug_info_t *new_id;
798 unsigned long flags;
799
800 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
801 return -EINVAL;
802
803 new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
804 id->level, ALL_AREAS);
805 if (!new_id) {
806 pr_info("Allocating memory for %i pages failed\n",
807 pages_per_area);
808 return -ENOMEM;
809 }
810
811 spin_lock_irqsave(&id->lock, flags);
812 debug_events_append(new_id, id);
813 debug_areas_swap(new_id, id);
814 debug_info_free(new_id);
815 spin_unlock_irqrestore(&id->lock, flags);
816 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
817
818 return 0;
819}
820
821/**
822 * debug_set_level() - Sets new actual debug level if new_level is valid.
823 *
824 * @id: handle for debug log
825 * @new_level: new debug level
826 *
827 * Return:
828 * none
829 */
830void debug_set_level(debug_info_t *id, int new_level)
831{
832 unsigned long flags;
833
834 if (!id)
835 return;
836
837 if (new_level == DEBUG_OFF_LEVEL) {
838 pr_info("%s: switched off\n", id->name);
839 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
840 pr_info("%s: level %i is out of range (%i - %i)\n",
841 id->name, new_level, 0, DEBUG_MAX_LEVEL);
842 return;
843 }
844
845 spin_lock_irqsave(&id->lock, flags);
846 id->level = new_level;
847 spin_unlock_irqrestore(&id->lock, flags);
848}
849EXPORT_SYMBOL(debug_set_level);
850
851/*
852 * proceed_active_entry:
853 * - set active entry to next in the ring buffer
854 */
855static inline void proceed_active_entry(debug_info_t *id)
856{
857 if ((id->active_entries[id->active_area] += id->entry_size)
858 > (PAGE_SIZE - id->entry_size)) {
859 id->active_entries[id->active_area] = 0;
860 id->active_pages[id->active_area] =
861 (id->active_pages[id->active_area] + 1) %
862 id->pages_per_area;
863 }
864}
865
866/*
867 * proceed_active_area:
868 * - set active area to next in the ring buffer
869 */
870static inline void proceed_active_area(debug_info_t *id)
871{
872 id->active_area++;
873 id->active_area = id->active_area % id->nr_areas;
874}
875
876/*
877 * get_active_entry:
878 */
879static inline debug_entry_t *get_active_entry(debug_info_t *id)
880{
881 return (debug_entry_t *) (((char *) id->areas[id->active_area]
882 [id->active_pages[id->active_area]]) +
883 id->active_entries[id->active_area]);
884}
885
886/* Swap debug areas of a and b. */
887static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
888{
889 swap(a->nr_areas, b->nr_areas);
890 swap(a->pages_per_area, b->pages_per_area);
891 swap(a->areas, b->areas);
892 swap(a->active_area, b->active_area);
893 swap(a->active_pages, b->active_pages);
894 swap(a->active_entries, b->active_entries);
895}
896
897/* Append all debug events in active area from source to destination log. */
898static void debug_events_append(debug_info_t *dest, debug_info_t *src)
899{
900 debug_entry_t *from, *to, *last;
901
902 if (!src->areas || !dest->areas)
903 return;
904
905 /* Loop over all entries in src, starting with oldest. */
906 from = get_active_entry(src);
907 last = from;
908 do {
909 if (from->clock != 0LL) {
910 to = get_active_entry(dest);
911 memset(to, 0, dest->entry_size);
912 memcpy(to, from, min(src->entry_size,
913 dest->entry_size));
914 proceed_active_entry(dest);
915 }
916
917 proceed_active_entry(src);
918 from = get_active_entry(src);
919 } while (from != last);
920}
921
922/*
923 * debug_finish_entry:
924 * - set timestamp, caller address, cpu number etc.
925 */
926
927static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
928 int level, int exception)
929{
930 unsigned long timestamp;
931 union tod_clock clk;
932
933 store_tod_clock_ext(&clk);
934 timestamp = clk.us;
935 timestamp -= TOD_UNIX_EPOCH >> 12;
936 active->clock = timestamp;
937 active->cpu = smp_processor_id();
938 active->caller = __builtin_return_address(0);
939 active->exception = exception;
940 active->level = level;
941 proceed_active_entry(id);
942 if (exception)
943 proceed_active_area(id);
944}
945
946static int debug_stoppable = 1;
947static int debug_active = 1;
948
949#define CTL_S390DBF_STOPPABLE 5678
950#define CTL_S390DBF_ACTIVE 5679
951
952/*
953 * proc handler for the running debug_active sysctl
954 * always allow read, allow write only if debug_stoppable is set or
955 * if debug_active is already off
956 */
957static int s390dbf_procactive(struct ctl_table *table, int write,
958 void *buffer, size_t *lenp, loff_t *ppos)
959{
960 if (!write || debug_stoppable || !debug_active)
961 return proc_dointvec(table, write, buffer, lenp, ppos);
962 else
963 return 0;
964}
965
966static struct ctl_table s390dbf_table[] = {
967 {
968 .procname = "debug_stoppable",
969 .data = &debug_stoppable,
970 .maxlen = sizeof(int),
971 .mode = S_IRUGO | S_IWUSR,
972 .proc_handler = proc_dointvec,
973 },
974 {
975 .procname = "debug_active",
976 .data = &debug_active,
977 .maxlen = sizeof(int),
978 .mode = S_IRUGO | S_IWUSR,
979 .proc_handler = s390dbf_procactive,
980 },
981 { }
982};
983
984static struct ctl_table s390dbf_dir_table[] = {
985 {
986 .procname = "s390dbf",
987 .maxlen = 0,
988 .mode = S_IRUGO | S_IXUGO,
989 .child = s390dbf_table,
990 },
991 { }
992};
993
994static struct ctl_table_header *s390dbf_sysctl_header;
995
996/**
997 * debug_stop_all() - stops the debug feature if stopping is allowed.
998 *
999 * Return:
1000 * - none
1001 *
1002 * Currently used in case of a kernel oops.
1003 */
1004void debug_stop_all(void)
1005{
1006 if (debug_stoppable)
1007 debug_active = 0;
1008}
1009EXPORT_SYMBOL(debug_stop_all);
1010
1011/**
1012 * debug_set_critical() - event/exception functions try lock instead of spin.
1013 *
1014 * Return:
1015 * - none
1016 *
1017 * Currently used in case of stopping all CPUs but the current one.
1018 * Once in this state, functions to write a debug entry for an
1019 * event or exception no longer spin on the debug area lock,
1020 * but only try to get it and fail if they do not get the lock.
1021 */
1022void debug_set_critical(void)
1023{
1024 debug_critical = 1;
1025}
1026
1027/*
1028 * debug_event_common:
1029 * - write debug entry with given size
1030 */
1031debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
1032 int len)
1033{
1034 debug_entry_t *active;
1035 unsigned long flags;
1036
1037 if (!debug_active || !id->areas)
1038 return NULL;
1039 if (debug_critical) {
1040 if (!spin_trylock_irqsave(&id->lock, flags))
1041 return NULL;
1042 } else {
1043 spin_lock_irqsave(&id->lock, flags);
1044 }
1045 do {
1046 active = get_active_entry(id);
1047 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1048 if (len < id->buf_size)
1049 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1050 debug_finish_entry(id, active, level, 0);
1051 len -= id->buf_size;
1052 buf += id->buf_size;
1053 } while (len > 0);
1054
1055 spin_unlock_irqrestore(&id->lock, flags);
1056 return active;
1057}
1058EXPORT_SYMBOL(debug_event_common);
1059
1060/*
1061 * debug_exception_common:
1062 * - write debug entry with given size and switch to next debug area
1063 */
1064debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1065 const void *buf, int len)
1066{
1067 debug_entry_t *active;
1068 unsigned long flags;
1069
1070 if (!debug_active || !id->areas)
1071 return NULL;
1072 if (debug_critical) {
1073 if (!spin_trylock_irqsave(&id->lock, flags))
1074 return NULL;
1075 } else {
1076 spin_lock_irqsave(&id->lock, flags);
1077 }
1078 do {
1079 active = get_active_entry(id);
1080 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1081 if (len < id->buf_size)
1082 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1083 debug_finish_entry(id, active, level, len <= id->buf_size);
1084 len -= id->buf_size;
1085 buf += id->buf_size;
1086 } while (len > 0);
1087
1088 spin_unlock_irqrestore(&id->lock, flags);
1089 return active;
1090}
1091EXPORT_SYMBOL(debug_exception_common);
1092
1093/*
1094 * counts arguments in format string for sprintf view
1095 */
1096static inline int debug_count_numargs(char *string)
1097{
1098 int numargs = 0;
1099
1100 while (*string) {
1101 if (*string++ == '%')
1102 numargs++;
1103 }
1104 return numargs;
1105}
1106
1107/*
1108 * debug_sprintf_event:
1109 */
1110debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1111{
1112 debug_sprintf_entry_t *curr_event;
1113 debug_entry_t *active;
1114 unsigned long flags;
1115 int numargs, idx;
1116 va_list ap;
1117
1118 if (!debug_active || !id->areas)
1119 return NULL;
1120 numargs = debug_count_numargs(string);
1121
1122 if (debug_critical) {
1123 if (!spin_trylock_irqsave(&id->lock, flags))
1124 return NULL;
1125 } else {
1126 spin_lock_irqsave(&id->lock, flags);
1127 }
1128 active = get_active_entry(id);
1129 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1130 va_start(ap, string);
1131 curr_event->string = string;
1132 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1133 curr_event->args[idx] = va_arg(ap, long);
1134 va_end(ap);
1135 debug_finish_entry(id, active, level, 0);
1136 spin_unlock_irqrestore(&id->lock, flags);
1137
1138 return active;
1139}
1140EXPORT_SYMBOL(__debug_sprintf_event);
1141
1142/*
1143 * debug_sprintf_exception:
1144 */
1145debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1146{
1147 debug_sprintf_entry_t *curr_event;
1148 debug_entry_t *active;
1149 unsigned long flags;
1150 int numargs, idx;
1151 va_list ap;
1152
1153 if (!debug_active || !id->areas)
1154 return NULL;
1155
1156 numargs = debug_count_numargs(string);
1157
1158 if (debug_critical) {
1159 if (!spin_trylock_irqsave(&id->lock, flags))
1160 return NULL;
1161 } else {
1162 spin_lock_irqsave(&id->lock, flags);
1163 }
1164 active = get_active_entry(id);
1165 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1166 va_start(ap, string);
1167 curr_event->string = string;
1168 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1169 curr_event->args[idx] = va_arg(ap, long);
1170 va_end(ap);
1171 debug_finish_entry(id, active, level, 1);
1172 spin_unlock_irqrestore(&id->lock, flags);
1173
1174 return active;
1175}
1176EXPORT_SYMBOL(__debug_sprintf_exception);
1177
1178/**
1179 * debug_register_view() - registers new debug view and creates debugfs
1180 * dir entry
1181 *
1182 * @id: handle for debug log
1183 * @view: pointer to debug view struct
1184 *
1185 * Return:
1186 * - 0 : ok
1187 * - < 0: Error
1188 */
1189int debug_register_view(debug_info_t *id, struct debug_view *view)
1190{
1191 unsigned long flags;
1192 struct dentry *pde;
1193 umode_t mode;
1194 int rc = 0;
1195 int i;
1196
1197 if (!id)
1198 goto out;
1199 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1200 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1201 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1202 if (!view->input_proc)
1203 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1204 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1205 id, &debug_file_ops);
1206 spin_lock_irqsave(&id->lock, flags);
1207 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1208 if (!id->views[i])
1209 break;
1210 }
1211 if (i == DEBUG_MAX_VIEWS) {
1212 rc = -1;
1213 } else {
1214 id->views[i] = view;
1215 id->debugfs_entries[i] = pde;
1216 }
1217 spin_unlock_irqrestore(&id->lock, flags);
1218 if (rc) {
1219 pr_err("Registering view %s/%s would exceed the maximum "
1220 "number of views %i\n", id->name, view->name, i);
1221 debugfs_remove(pde);
1222 }
1223out:
1224 return rc;
1225}
1226EXPORT_SYMBOL(debug_register_view);
1227
1228/**
1229 * debug_unregister_view() - unregisters debug view and removes debugfs
1230 * dir entry
1231 *
1232 * @id: handle for debug log
1233 * @view: pointer to debug view struct
1234 *
1235 * Return:
1236 * - 0 : ok
1237 * - < 0: Error
1238 */
1239int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1240{
1241 struct dentry *dentry = NULL;
1242 unsigned long flags;
1243 int i, rc = 0;
1244
1245 if (!id)
1246 goto out;
1247 spin_lock_irqsave(&id->lock, flags);
1248 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1249 if (id->views[i] == view)
1250 break;
1251 }
1252 if (i == DEBUG_MAX_VIEWS) {
1253 rc = -1;
1254 } else {
1255 dentry = id->debugfs_entries[i];
1256 id->views[i] = NULL;
1257 id->debugfs_entries[i] = NULL;
1258 }
1259 spin_unlock_irqrestore(&id->lock, flags);
1260 debugfs_remove(dentry);
1261out:
1262 return rc;
1263}
1264EXPORT_SYMBOL(debug_unregister_view);
1265
1266static inline char *debug_get_user_string(const char __user *user_buf,
1267 size_t user_len)
1268{
1269 char *buffer;
1270
1271 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1272 if (!buffer)
1273 return ERR_PTR(-ENOMEM);
1274 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1275 kfree(buffer);
1276 return ERR_PTR(-EFAULT);
1277 }
1278 /* got the string, now strip linefeed. */
1279 if (buffer[user_len - 1] == '\n')
1280 buffer[user_len - 1] = 0;
1281 else
1282 buffer[user_len] = 0;
1283 return buffer;
1284}
1285
1286static inline int debug_get_uint(char *buf)
1287{
1288 int rc;
1289
1290 buf = skip_spaces(buf);
1291 rc = simple_strtoul(buf, &buf, 10);
1292 if (*buf)
1293 rc = -EINVAL;
1294 return rc;
1295}
1296
1297/*
1298 * functions for debug-views
1299 ***********************************
1300*/
1301
1302/*
1303 * prints out actual debug level
1304 */
1305
1306static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1307 char *out_buf)
1308{
1309 return sprintf(out_buf, "%i\n", id->pages_per_area);
1310}
1311
1312/*
1313 * reads new size (number of pages per debug area)
1314 */
1315
1316static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1317 struct file *file, const char __user *user_buf,
1318 size_t user_len, loff_t *offset)
1319{
1320 int rc, new_pages;
1321 char *str;
1322
1323 if (user_len > 0x10000)
1324 user_len = 0x10000;
1325 if (*offset != 0) {
1326 rc = -EPIPE;
1327 goto out;
1328 }
1329 str = debug_get_user_string(user_buf, user_len);
1330 if (IS_ERR(str)) {
1331 rc = PTR_ERR(str);
1332 goto out;
1333 }
1334 new_pages = debug_get_uint(str);
1335 if (new_pages < 0) {
1336 rc = -EINVAL;
1337 goto free_str;
1338 }
1339 rc = debug_set_size(id, id->nr_areas, new_pages);
1340 if (rc != 0) {
1341 rc = -EINVAL;
1342 goto free_str;
1343 }
1344 rc = user_len;
1345free_str:
1346 kfree(str);
1347out:
1348 *offset += user_len;
1349 return rc; /* number of input characters */
1350}
1351
1352/*
1353 * prints out actual debug level
1354 */
1355static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1356 char *out_buf)
1357{
1358 int rc = 0;
1359
1360 if (id->level == DEBUG_OFF_LEVEL)
1361 rc = sprintf(out_buf, "-\n");
1362 else
1363 rc = sprintf(out_buf, "%i\n", id->level);
1364 return rc;
1365}
1366
1367/*
1368 * reads new debug level
1369 */
1370static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1371 struct file *file, const char __user *user_buf,
1372 size_t user_len, loff_t *offset)
1373{
1374 int rc, new_level;
1375 char *str;
1376
1377 if (user_len > 0x10000)
1378 user_len = 0x10000;
1379 if (*offset != 0) {
1380 rc = -EPIPE;
1381 goto out;
1382 }
1383 str = debug_get_user_string(user_buf, user_len);
1384 if (IS_ERR(str)) {
1385 rc = PTR_ERR(str);
1386 goto out;
1387 }
1388 if (str[0] == '-') {
1389 debug_set_level(id, DEBUG_OFF_LEVEL);
1390 rc = user_len;
1391 goto free_str;
1392 } else {
1393 new_level = debug_get_uint(str);
1394 }
1395 if (new_level < 0) {
1396 pr_warn("%s is not a valid level for a debug feature\n", str);
1397 rc = -EINVAL;
1398 } else {
1399 debug_set_level(id, new_level);
1400 rc = user_len;
1401 }
1402free_str:
1403 kfree(str);
1404out:
1405 *offset += user_len;
1406 return rc; /* number of input characters */
1407}
1408
1409/*
1410 * flushes debug areas
1411 */
1412static void debug_flush(debug_info_t *id, int area)
1413{
1414 unsigned long flags;
1415 int i, j;
1416
1417 if (!id || !id->areas)
1418 return;
1419 spin_lock_irqsave(&id->lock, flags);
1420 if (area == DEBUG_FLUSH_ALL) {
1421 id->active_area = 0;
1422 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1423 for (i = 0; i < id->nr_areas; i++) {
1424 id->active_pages[i] = 0;
1425 for (j = 0; j < id->pages_per_area; j++)
1426 memset(id->areas[i][j], 0, PAGE_SIZE);
1427 }
1428 } else if (area >= 0 && area < id->nr_areas) {
1429 id->active_entries[area] = 0;
1430 id->active_pages[area] = 0;
1431 for (i = 0; i < id->pages_per_area; i++)
1432 memset(id->areas[area][i], 0, PAGE_SIZE);
1433 }
1434 spin_unlock_irqrestore(&id->lock, flags);
1435}
1436
1437/*
1438 * view function: flushes debug areas
1439 */
1440static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1441 struct file *file, const char __user *user_buf,
1442 size_t user_len, loff_t *offset)
1443{
1444 char input_buf[1];
1445 int rc = user_len;
1446
1447 if (user_len > 0x10000)
1448 user_len = 0x10000;
1449 if (*offset != 0) {
1450 rc = -EPIPE;
1451 goto out;
1452 }
1453 if (copy_from_user(input_buf, user_buf, 1)) {
1454 rc = -EFAULT;
1455 goto out;
1456 }
1457 if (input_buf[0] == '-') {
1458 debug_flush(id, DEBUG_FLUSH_ALL);
1459 goto out;
1460 }
1461 if (isdigit(input_buf[0])) {
1462 int area = ((int) input_buf[0] - (int) '0');
1463
1464 debug_flush(id, area);
1465 goto out;
1466 }
1467
1468 pr_info("Flushing debug data failed because %c is not a valid "
1469 "area\n", input_buf[0]);
1470
1471out:
1472 *offset += user_len;
1473 return rc; /* number of input characters */
1474}
1475
1476/*
1477 * prints debug data in hex/ascii format
1478 */
1479static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1480 char *out_buf, const char *in_buf)
1481{
1482 int i, rc = 0;
1483
1484 for (i = 0; i < id->buf_size; i++)
1485 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1486 rc += sprintf(out_buf + rc, "| ");
1487 for (i = 0; i < id->buf_size; i++) {
1488 unsigned char c = in_buf[i];
1489
1490 if (isascii(c) && isprint(c))
1491 rc += sprintf(out_buf + rc, "%c", c);
1492 else
1493 rc += sprintf(out_buf + rc, ".");
1494 }
1495 rc += sprintf(out_buf + rc, "\n");
1496 return rc;
1497}
1498
1499/*
1500 * prints header for debug entry
1501 */
1502int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1503 int area, debug_entry_t *entry, char *out_buf)
1504{
1505 unsigned long sec, usec;
1506 unsigned long caller;
1507 unsigned int level;
1508 char *except_str;
1509 int rc = 0;
1510
1511 level = entry->level;
1512 sec = entry->clock;
1513 usec = do_div(sec, USEC_PER_SEC);
1514
1515 if (entry->exception)
1516 except_str = "*";
1517 else
1518 except_str = "-";
1519 caller = (unsigned long) entry->caller;
1520 rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ",
1521 area, sec, usec, level, except_str,
1522 entry->cpu, (void *)caller);
1523 return rc;
1524}
1525EXPORT_SYMBOL(debug_dflt_header_fn);
1526
1527/*
1528 * prints debug data sprintf-formated:
1529 * debug_sprinf_event/exception calls must be used together with this view
1530 */
1531
1532#define DEBUG_SPRINTF_MAX_ARGS 10
1533
1534static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1535 char *out_buf, const char *inbuf)
1536{
1537 debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
1538 int num_longs, num_used_args = 0, i, rc = 0;
1539 int index[DEBUG_SPRINTF_MAX_ARGS];
1540
1541 /* count of longs fit into one entry */
1542 num_longs = id->buf_size / sizeof(long);
1543
1544 if (num_longs < 1)
1545 goto out; /* bufsize of entry too small */
1546 if (num_longs == 1) {
1547 /* no args, we use only the string */
1548 strcpy(out_buf, curr_event->string);
1549 rc = strlen(curr_event->string);
1550 goto out;
1551 }
1552
1553 /* number of arguments used for sprintf (without the format string) */
1554 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1555
1556 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1557
1558 for (i = 0; i < num_used_args; i++)
1559 index[i] = i;
1560
1561 rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1562 curr_event->args[index[1]], curr_event->args[index[2]],
1563 curr_event->args[index[3]], curr_event->args[index[4]],
1564 curr_event->args[index[5]], curr_event->args[index[6]],
1565 curr_event->args[index[7]], curr_event->args[index[8]],
1566 curr_event->args[index[9]]);
1567out:
1568 return rc;
1569}
1570
1571/*
1572 * debug_init:
1573 * - is called exactly once to initialize the debug feature
1574 */
1575static int __init debug_init(void)
1576{
1577 s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1578 mutex_lock(&debug_mutex);
1579 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1580 initialized = 1;
1581 mutex_unlock(&debug_mutex);
1582 return 0;
1583}
1584postcore_initcall(debug_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * S/390 debug facility
4 *
5 * Copyright IBM Corp. 1999, 2020
6 *
7 * Author(s): Michael Holzheu (holzheu@de.ibm.com),
8 * Holger Smolinski (Holger.Smolinski@de.ibm.com)
9 *
10 * Bugreports to: <Linux390@de.ibm.com>
11 */
12
13#define KMSG_COMPONENT "s390dbf"
14#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16#include <linux/stddef.h>
17#include <linux/kernel.h>
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/ctype.h>
21#include <linux/string.h>
22#include <linux/sysctl.h>
23#include <linux/uaccess.h>
24#include <linux/export.h>
25#include <linux/init.h>
26#include <linux/fs.h>
27#include <linux/minmax.h>
28#include <linux/debugfs.h>
29
30#include <asm/debug.h>
31
32#define DEBUG_PROLOG_ENTRY -1
33
34#define ALL_AREAS 0 /* copy all debug areas */
35#define NO_AREAS 1 /* copy no debug areas */
36
37/* typedefs */
38
39typedef struct file_private_info {
40 loff_t offset; /* offset of last read in file */
41 int act_area; /* number of last formatted area */
42 int act_page; /* act page in given area */
43 int act_entry; /* last formatted entry (offset */
44 /* relative to beginning of last */
45 /* formatted page) */
46 size_t act_entry_offset; /* up to this offset we copied */
47 /* in last read the last formatted */
48 /* entry to userland */
49 char temp_buf[2048]; /* buffer for output */
50 debug_info_t *debug_info_org; /* original debug information */
51 debug_info_t *debug_info_snap; /* snapshot of debug information */
52 struct debug_view *view; /* used view of debug info */
53} file_private_info_t;
54
55typedef struct {
56 char *string;
57 /*
58 * This assumes that all args are converted into longs
59 * on L/390 this is the case for all types of parameter
60 * except of floats, and long long (32 bit)
61 *
62 */
63 long args[];
64} debug_sprintf_entry_t;
65
66/* internal function prototypes */
67
68static int debug_init(void);
69static ssize_t debug_output(struct file *file, char __user *user_buf,
70 size_t user_len, loff_t *offset);
71static ssize_t debug_input(struct file *file, const char __user *user_buf,
72 size_t user_len, loff_t *offset);
73static int debug_open(struct inode *inode, struct file *file);
74static int debug_close(struct inode *inode, struct file *file);
75static debug_info_t *debug_info_create(const char *name, int pages_per_area,
76 int nr_areas, int buf_size, umode_t mode);
77static void debug_info_get(debug_info_t *);
78static void debug_info_put(debug_info_t *);
79static int debug_prolog_level_fn(debug_info_t *id,
80 struct debug_view *view, char *out_buf,
81 size_t out_buf_size);
82static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
83 struct file *file, const char __user *user_buf,
84 size_t user_buf_size, loff_t *offset);
85static int debug_prolog_pages_fn(debug_info_t *id,
86 struct debug_view *view, char *out_buf,
87 size_t out_buf_size);
88static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
89 struct file *file, const char __user *user_buf,
90 size_t user_buf_size, loff_t *offset);
91static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
92 struct file *file, const char __user *user_buf,
93 size_t user_buf_size, loff_t *offset);
94static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
95 char *out_buf, size_t out_buf_size,
96 const char *in_buf);
97static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
98 char *out_buf, size_t out_buf_size,
99 const char *inbuf);
100static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
101static void debug_events_append(debug_info_t *dest, debug_info_t *src);
102
103/* globals */
104
105struct debug_view debug_hex_ascii_view = {
106 "hex_ascii",
107 NULL,
108 &debug_dflt_header_fn,
109 &debug_hex_ascii_format_fn,
110 NULL,
111 NULL
112};
113EXPORT_SYMBOL(debug_hex_ascii_view);
114
115static struct debug_view debug_level_view = {
116 "level",
117 &debug_prolog_level_fn,
118 NULL,
119 NULL,
120 &debug_input_level_fn,
121 NULL
122};
123
124static struct debug_view debug_pages_view = {
125 "pages",
126 &debug_prolog_pages_fn,
127 NULL,
128 NULL,
129 &debug_input_pages_fn,
130 NULL
131};
132
133static struct debug_view debug_flush_view = {
134 "flush",
135 NULL,
136 NULL,
137 NULL,
138 &debug_input_flush_fn,
139 NULL
140};
141
142struct debug_view debug_sprintf_view = {
143 "sprintf",
144 NULL,
145 &debug_dflt_header_fn,
146 &debug_sprintf_format_fn,
147 NULL,
148 NULL
149};
150EXPORT_SYMBOL(debug_sprintf_view);
151
152/* used by dump analysis tools to determine version of debug feature */
153static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
154
155/* static globals */
156
157static debug_info_t *debug_area_first;
158static debug_info_t *debug_area_last;
159static DEFINE_MUTEX(debug_mutex);
160
161static int initialized;
162static int debug_critical;
163
164static const struct file_operations debug_file_ops = {
165 .owner = THIS_MODULE,
166 .read = debug_output,
167 .write = debug_input,
168 .open = debug_open,
169 .release = debug_close,
170};
171
172static struct dentry *debug_debugfs_root_entry;
173
174/* functions */
175
176/*
177 * debug_areas_alloc
178 * - Debug areas are implemented as a threedimensonal array:
179 * areas[areanumber][pagenumber][pageoffset]
180 */
181
182static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
183{
184 debug_entry_t ***areas;
185 int i, j;
186
187 areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
188 if (!areas)
189 goto fail_malloc_areas;
190 for (i = 0; i < nr_areas; i++) {
191 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
192 areas[i] = kmalloc_array(pages_per_area,
193 sizeof(debug_entry_t *),
194 GFP_KERNEL | __GFP_NOWARN);
195 if (!areas[i])
196 goto fail_malloc_areas2;
197 for (j = 0; j < pages_per_area; j++) {
198 areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
199 if (!areas[i][j]) {
200 for (j--; j >= 0 ; j--)
201 kfree(areas[i][j]);
202 kfree(areas[i]);
203 goto fail_malloc_areas2;
204 }
205 }
206 }
207 return areas;
208
209fail_malloc_areas2:
210 for (i--; i >= 0; i--) {
211 for (j = 0; j < pages_per_area; j++)
212 kfree(areas[i][j]);
213 kfree(areas[i]);
214 }
215 kfree(areas);
216fail_malloc_areas:
217 return NULL;
218}
219
220/*
221 * debug_info_alloc
222 * - alloc new debug-info
223 */
224static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
225 int nr_areas, int buf_size, int level,
226 int mode)
227{
228 debug_info_t *rc;
229
230 /* alloc everything */
231 rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
232 if (!rc)
233 goto fail_malloc_rc;
234 rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
235 if (!rc->active_entries)
236 goto fail_malloc_active_entries;
237 rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
238 if (!rc->active_pages)
239 goto fail_malloc_active_pages;
240 if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
241 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
242 if (!rc->areas)
243 goto fail_malloc_areas;
244 } else {
245 rc->areas = NULL;
246 }
247
248 /* initialize members */
249 spin_lock_init(&rc->lock);
250 rc->pages_per_area = pages_per_area;
251 rc->nr_areas = nr_areas;
252 rc->active_area = 0;
253 rc->level = level;
254 rc->buf_size = buf_size;
255 rc->entry_size = sizeof(debug_entry_t) + buf_size;
256 strscpy(rc->name, name, sizeof(rc->name));
257 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
258 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
259 refcount_set(&(rc->ref_count), 0);
260
261 return rc;
262
263fail_malloc_areas:
264 kfree(rc->active_pages);
265fail_malloc_active_pages:
266 kfree(rc->active_entries);
267fail_malloc_active_entries:
268 kfree(rc);
269fail_malloc_rc:
270 return NULL;
271}
272
273/*
274 * debug_areas_free
275 * - free all debug areas
276 */
277static void debug_areas_free(debug_info_t *db_info)
278{
279 int i, j;
280
281 if (!db_info->areas)
282 return;
283 for (i = 0; i < db_info->nr_areas; i++) {
284 for (j = 0; j < db_info->pages_per_area; j++)
285 kfree(db_info->areas[i][j]);
286 kfree(db_info->areas[i]);
287 }
288 kfree(db_info->areas);
289 db_info->areas = NULL;
290}
291
292/*
293 * debug_info_free
294 * - free memory debug-info
295 */
296static void debug_info_free(debug_info_t *db_info)
297{
298 debug_areas_free(db_info);
299 kfree(db_info->active_entries);
300 kfree(db_info->active_pages);
301 kfree(db_info);
302}
303
304/*
305 * debug_info_create
306 * - create new debug-info
307 */
308
309static debug_info_t *debug_info_create(const char *name, int pages_per_area,
310 int nr_areas, int buf_size, umode_t mode)
311{
312 debug_info_t *rc;
313
314 rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
315 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
316 if (!rc)
317 goto out;
318
319 rc->mode = mode & ~S_IFMT;
320 refcount_set(&rc->ref_count, 1);
321out:
322 return rc;
323}
324
325/*
326 * debug_info_copy
327 * - copy debug-info
328 */
329static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
330{
331 unsigned long flags;
332 debug_info_t *rc;
333 int i, j;
334
335 /* get a consistent copy of the debug areas */
336 do {
337 rc = debug_info_alloc(in->name, in->pages_per_area,
338 in->nr_areas, in->buf_size, in->level, mode);
339 spin_lock_irqsave(&in->lock, flags);
340 if (!rc)
341 goto out;
342 /* has something changed in the meantime ? */
343 if ((rc->pages_per_area == in->pages_per_area) &&
344 (rc->nr_areas == in->nr_areas)) {
345 break;
346 }
347 spin_unlock_irqrestore(&in->lock, flags);
348 debug_info_free(rc);
349 } while (1);
350
351 if (mode == NO_AREAS)
352 goto out;
353
354 for (i = 0; i < in->nr_areas; i++) {
355 for (j = 0; j < in->pages_per_area; j++)
356 memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
357 }
358out:
359 spin_unlock_irqrestore(&in->lock, flags);
360 return rc;
361}
362
363/*
364 * debug_info_get
365 * - increments reference count for debug-info
366 */
367static void debug_info_get(debug_info_t *db_info)
368{
369 if (db_info)
370 refcount_inc(&db_info->ref_count);
371}
372
373/*
374 * debug_info_put:
375 * - decreases reference count for debug-info and frees it if necessary
376 */
377static void debug_info_put(debug_info_t *db_info)
378{
379 if (!db_info)
380 return;
381 if (refcount_dec_and_test(&db_info->ref_count))
382 debug_info_free(db_info);
383}
384
385/*
386 * debug_format_entry:
387 * - format one debug entry and return size of formatted data
388 */
389static int debug_format_entry(file_private_info_t *p_info)
390{
391 debug_info_t *id_snap = p_info->debug_info_snap;
392 struct debug_view *view = p_info->view;
393 debug_entry_t *act_entry;
394 size_t len = 0;
395
396 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
397 /* print prolog */
398 if (view->prolog_proc) {
399 len += view->prolog_proc(id_snap, view, p_info->temp_buf,
400 sizeof(p_info->temp_buf));
401 }
402 goto out;
403 }
404 if (!id_snap->areas) /* this is true, if we have a prolog only view */
405 goto out; /* or if 'pages_per_area' is 0 */
406 act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
407 [p_info->act_page] + p_info->act_entry);
408
409 if (act_entry->clock == 0LL)
410 goto out; /* empty entry */
411 if (view->header_proc) {
412 len += view->header_proc(id_snap, view, p_info->act_area,
413 act_entry, p_info->temp_buf + len,
414 sizeof(p_info->temp_buf) - len);
415 }
416 if (view->format_proc) {
417 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
418 sizeof(p_info->temp_buf) - len,
419 DEBUG_DATA(act_entry));
420 }
421out:
422 return len;
423}
424
425/*
426 * debug_next_entry:
427 * - goto next entry in p_info
428 */
429static inline int debug_next_entry(file_private_info_t *p_info)
430{
431 debug_info_t *id;
432
433 id = p_info->debug_info_snap;
434 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
435 p_info->act_entry = 0;
436 p_info->act_page = 0;
437 goto out;
438 }
439 if (!id->areas)
440 return 1;
441 p_info->act_entry += id->entry_size;
442 /* switch to next page, if we reached the end of the page */
443 if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
444 /* next page */
445 p_info->act_entry = 0;
446 p_info->act_page += 1;
447 if ((p_info->act_page % id->pages_per_area) == 0) {
448 /* next area */
449 p_info->act_area++;
450 p_info->act_page = 0;
451 }
452 if (p_info->act_area >= id->nr_areas)
453 return 1;
454 }
455out:
456 return 0;
457}
458
459/*
460 * debug_output:
461 * - called for user read()
462 * - copies formatted debug entries to the user buffer
463 */
464static ssize_t debug_output(struct file *file, /* file descriptor */
465 char __user *user_buf, /* user buffer */
466 size_t len, /* length of buffer */
467 loff_t *offset) /* offset in the file */
468{
469 size_t count = 0;
470 size_t entry_offset;
471 file_private_info_t *p_info;
472
473 p_info = (file_private_info_t *) file->private_data;
474 if (*offset != p_info->offset)
475 return -EPIPE;
476 if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
477 return 0;
478 entry_offset = p_info->act_entry_offset;
479 while (count < len) {
480 int formatted_line_residue;
481 int formatted_line_size;
482 int user_buf_residue;
483 size_t copy_size;
484
485 formatted_line_size = debug_format_entry(p_info);
486 formatted_line_residue = formatted_line_size - entry_offset;
487 user_buf_residue = len-count;
488 copy_size = min(user_buf_residue, formatted_line_residue);
489 if (copy_size) {
490 if (copy_to_user(user_buf + count, p_info->temp_buf
491 + entry_offset, copy_size))
492 return -EFAULT;
493 count += copy_size;
494 entry_offset += copy_size;
495 }
496 if (copy_size == formatted_line_residue) {
497 entry_offset = 0;
498 if (debug_next_entry(p_info))
499 goto out;
500 }
501 }
502out:
503 p_info->offset = *offset + count;
504 p_info->act_entry_offset = entry_offset;
505 *offset = p_info->offset;
506 return count;
507}
508
509/*
510 * debug_input:
511 * - called for user write()
512 * - calls input function of view
513 */
514static ssize_t debug_input(struct file *file, const char __user *user_buf,
515 size_t length, loff_t *offset)
516{
517 file_private_info_t *p_info;
518 int rc = 0;
519
520 mutex_lock(&debug_mutex);
521 p_info = ((file_private_info_t *) file->private_data);
522 if (p_info->view->input_proc) {
523 rc = p_info->view->input_proc(p_info->debug_info_org,
524 p_info->view, file, user_buf,
525 length, offset);
526 } else {
527 rc = -EPERM;
528 }
529 mutex_unlock(&debug_mutex);
530 return rc; /* number of input characters */
531}
532
533/*
534 * debug_open:
535 * - called for user open()
536 * - copies formatted output to private_data area of the file
537 * handle
538 */
539static int debug_open(struct inode *inode, struct file *file)
540{
541 debug_info_t *debug_info, *debug_info_snapshot;
542 file_private_info_t *p_info;
543 int i, rc = 0;
544
545 mutex_lock(&debug_mutex);
546 debug_info = file_inode(file)->i_private;
547 /* find debug view */
548 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
549 if (!debug_info->views[i])
550 continue;
551 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
552 goto found; /* found view ! */
553 }
554 /* no entry found */
555 rc = -EINVAL;
556 goto out;
557
558found:
559
560 /* Make snapshot of current debug areas to get it consistent. */
561 /* To copy all the areas is only needed, if we have a view which */
562 /* formats the debug areas. */
563
564 if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
565 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
566 else
567 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
568
569 if (!debug_info_snapshot) {
570 rc = -ENOMEM;
571 goto out;
572 }
573 p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
574 if (!p_info) {
575 debug_info_free(debug_info_snapshot);
576 rc = -ENOMEM;
577 goto out;
578 }
579 p_info->offset = 0;
580 p_info->debug_info_snap = debug_info_snapshot;
581 p_info->debug_info_org = debug_info;
582 p_info->view = debug_info->views[i];
583 p_info->act_area = 0;
584 p_info->act_page = 0;
585 p_info->act_entry = DEBUG_PROLOG_ENTRY;
586 p_info->act_entry_offset = 0;
587 file->private_data = p_info;
588 debug_info_get(debug_info);
589 nonseekable_open(inode, file);
590out:
591 mutex_unlock(&debug_mutex);
592 return rc;
593}
594
595/*
596 * debug_close:
597 * - called for user close()
598 * - deletes private_data area of the file handle
599 */
600static int debug_close(struct inode *inode, struct file *file)
601{
602 file_private_info_t *p_info;
603
604 p_info = (file_private_info_t *) file->private_data;
605 if (p_info->debug_info_snap)
606 debug_info_free(p_info->debug_info_snap);
607 debug_info_put(p_info->debug_info_org);
608 kfree(file->private_data);
609 return 0; /* success */
610}
611
612/* Create debugfs entries and add to internal list. */
613static void _debug_register(debug_info_t *id)
614{
615 /* create root directory */
616 id->debugfs_root_entry = debugfs_create_dir(id->name,
617 debug_debugfs_root_entry);
618
619 /* append new element to linked list */
620 if (!debug_area_first) {
621 /* first element in list */
622 debug_area_first = id;
623 id->prev = NULL;
624 } else {
625 /* append element to end of list */
626 debug_area_last->next = id;
627 id->prev = debug_area_last;
628 }
629 debug_area_last = id;
630 id->next = NULL;
631
632 debug_register_view(id, &debug_level_view);
633 debug_register_view(id, &debug_flush_view);
634 debug_register_view(id, &debug_pages_view);
635}
636
637/**
638 * debug_register_mode() - creates and initializes debug area.
639 *
640 * @name: Name of debug log (e.g. used for debugfs entry)
641 * @pages_per_area: Number of pages, which will be allocated per area
642 * @nr_areas: Number of debug areas
643 * @buf_size: Size of data area in each debug entry
644 * @mode: File mode for debugfs files. E.g. S_IRWXUGO
645 * @uid: User ID for debugfs files. Currently only 0 is supported.
646 * @gid: Group ID for debugfs files. Currently only 0 is supported.
647 *
648 * Return:
649 * - Handle for generated debug area
650 * - %NULL if register failed
651 *
652 * Allocates memory for a debug log.
653 * Must not be called within an interrupt handler.
654 */
655debug_info_t *debug_register_mode(const char *name, int pages_per_area,
656 int nr_areas, int buf_size, umode_t mode,
657 uid_t uid, gid_t gid)
658{
659 debug_info_t *rc = NULL;
660
661 /* Since debugfs currently does not support uid/gid other than root, */
662 /* we do not allow gid/uid != 0 until we get support for that. */
663 if ((uid != 0) || (gid != 0))
664 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
665 BUG_ON(!initialized);
666
667 /* create new debug_info */
668 rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
669 if (rc) {
670 mutex_lock(&debug_mutex);
671 _debug_register(rc);
672 mutex_unlock(&debug_mutex);
673 } else {
674 pr_err("Registering debug feature %s failed\n", name);
675 }
676 return rc;
677}
678EXPORT_SYMBOL(debug_register_mode);
679
680/**
681 * debug_register() - creates and initializes debug area with default file mode.
682 *
683 * @name: Name of debug log (e.g. used for debugfs entry)
684 * @pages_per_area: Number of pages, which will be allocated per area
685 * @nr_areas: Number of debug areas
686 * @buf_size: Size of data area in each debug entry
687 *
688 * Return:
689 * - Handle for generated debug area
690 * - %NULL if register failed
691 *
692 * Allocates memory for a debug log.
693 * The debugfs file mode access permissions are read and write for user.
694 * Must not be called within an interrupt handler.
695 */
696debug_info_t *debug_register(const char *name, int pages_per_area,
697 int nr_areas, int buf_size)
698{
699 return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
700 S_IRUSR | S_IWUSR, 0, 0);
701}
702EXPORT_SYMBOL(debug_register);
703
704/**
705 * debug_register_static() - registers a static debug area
706 *
707 * @id: Handle for static debug area
708 * @pages_per_area: Number of pages per area
709 * @nr_areas: Number of debug areas
710 *
711 * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
712 *
713 * Note: This function is called automatically via an initcall generated by
714 * DEFINE_STATIC_DEBUG_INFO.
715 */
716void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
717{
718 unsigned long flags;
719 debug_info_t *copy;
720
721 if (!initialized) {
722 pr_err("Tried to register debug feature %s too early\n",
723 id->name);
724 return;
725 }
726
727 copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
728 id->level, ALL_AREAS);
729 if (!copy) {
730 pr_err("Registering debug feature %s failed\n", id->name);
731
732 /* Clear pointers to prevent tracing into released initdata. */
733 spin_lock_irqsave(&id->lock, flags);
734 id->areas = NULL;
735 id->active_pages = NULL;
736 id->active_entries = NULL;
737 spin_unlock_irqrestore(&id->lock, flags);
738
739 return;
740 }
741
742 /* Replace static trace area with dynamic copy. */
743 spin_lock_irqsave(&id->lock, flags);
744 debug_events_append(copy, id);
745 debug_areas_swap(id, copy);
746 spin_unlock_irqrestore(&id->lock, flags);
747
748 /* Clear pointers to initdata and discard copy. */
749 copy->areas = NULL;
750 copy->active_pages = NULL;
751 copy->active_entries = NULL;
752 debug_info_free(copy);
753
754 mutex_lock(&debug_mutex);
755 _debug_register(id);
756 mutex_unlock(&debug_mutex);
757}
758
759/* Remove debugfs entries and remove from internal list. */
760static void _debug_unregister(debug_info_t *id)
761{
762 int i;
763
764 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
765 if (!id->views[i])
766 continue;
767 debugfs_remove(id->debugfs_entries[i]);
768 }
769 debugfs_remove(id->debugfs_root_entry);
770 if (id == debug_area_first)
771 debug_area_first = id->next;
772 if (id == debug_area_last)
773 debug_area_last = id->prev;
774 if (id->prev)
775 id->prev->next = id->next;
776 if (id->next)
777 id->next->prev = id->prev;
778}
779
780/**
781 * debug_unregister() - give back debug area.
782 *
783 * @id: handle for debug log
784 *
785 * Return:
786 * none
787 */
788void debug_unregister(debug_info_t *id)
789{
790 if (!id)
791 return;
792 mutex_lock(&debug_mutex);
793 _debug_unregister(id);
794 mutex_unlock(&debug_mutex);
795
796 debug_info_put(id);
797}
798EXPORT_SYMBOL(debug_unregister);
799
800/*
801 * debug_set_size:
802 * - set area size (number of pages) and number of areas
803 */
804static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
805{
806 debug_info_t *new_id;
807 unsigned long flags;
808
809 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
810 return -EINVAL;
811
812 new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
813 id->level, ALL_AREAS);
814 if (!new_id) {
815 pr_info("Allocating memory for %i pages failed\n",
816 pages_per_area);
817 return -ENOMEM;
818 }
819
820 spin_lock_irqsave(&id->lock, flags);
821 debug_events_append(new_id, id);
822 debug_areas_swap(new_id, id);
823 debug_info_free(new_id);
824 spin_unlock_irqrestore(&id->lock, flags);
825 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
826
827 return 0;
828}
829
830/**
831 * debug_set_level() - Sets new actual debug level if new_level is valid.
832 *
833 * @id: handle for debug log
834 * @new_level: new debug level
835 *
836 * Return:
837 * none
838 */
839void debug_set_level(debug_info_t *id, int new_level)
840{
841 unsigned long flags;
842
843 if (!id)
844 return;
845
846 if (new_level == DEBUG_OFF_LEVEL) {
847 pr_info("%s: switched off\n", id->name);
848 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
849 pr_info("%s: level %i is out of range (%i - %i)\n",
850 id->name, new_level, 0, DEBUG_MAX_LEVEL);
851 return;
852 }
853
854 spin_lock_irqsave(&id->lock, flags);
855 id->level = new_level;
856 spin_unlock_irqrestore(&id->lock, flags);
857}
858EXPORT_SYMBOL(debug_set_level);
859
860/*
861 * proceed_active_entry:
862 * - set active entry to next in the ring buffer
863 */
864static inline void proceed_active_entry(debug_info_t *id)
865{
866 if ((id->active_entries[id->active_area] += id->entry_size)
867 > (PAGE_SIZE - id->entry_size)) {
868 id->active_entries[id->active_area] = 0;
869 id->active_pages[id->active_area] =
870 (id->active_pages[id->active_area] + 1) %
871 id->pages_per_area;
872 }
873}
874
875/*
876 * proceed_active_area:
877 * - set active area to next in the ring buffer
878 */
879static inline void proceed_active_area(debug_info_t *id)
880{
881 id->active_area++;
882 id->active_area = id->active_area % id->nr_areas;
883}
884
885/*
886 * get_active_entry:
887 */
888static inline debug_entry_t *get_active_entry(debug_info_t *id)
889{
890 return (debug_entry_t *) (((char *) id->areas[id->active_area]
891 [id->active_pages[id->active_area]]) +
892 id->active_entries[id->active_area]);
893}
894
895/* Swap debug areas of a and b. */
896static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
897{
898 swap(a->nr_areas, b->nr_areas);
899 swap(a->pages_per_area, b->pages_per_area);
900 swap(a->areas, b->areas);
901 swap(a->active_area, b->active_area);
902 swap(a->active_pages, b->active_pages);
903 swap(a->active_entries, b->active_entries);
904}
905
906/* Append all debug events in active area from source to destination log. */
907static void debug_events_append(debug_info_t *dest, debug_info_t *src)
908{
909 debug_entry_t *from, *to, *last;
910
911 if (!src->areas || !dest->areas)
912 return;
913
914 /* Loop over all entries in src, starting with oldest. */
915 from = get_active_entry(src);
916 last = from;
917 do {
918 if (from->clock != 0LL) {
919 to = get_active_entry(dest);
920 memset(to, 0, dest->entry_size);
921 memcpy(to, from, min(src->entry_size,
922 dest->entry_size));
923 proceed_active_entry(dest);
924 }
925
926 proceed_active_entry(src);
927 from = get_active_entry(src);
928 } while (from != last);
929}
930
931/*
932 * debug_finish_entry:
933 * - set timestamp, caller address, cpu number etc.
934 */
935
936static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
937 int level, int exception)
938{
939 unsigned long timestamp;
940 union tod_clock clk;
941
942 store_tod_clock_ext(&clk);
943 timestamp = clk.us;
944 timestamp -= TOD_UNIX_EPOCH >> 12;
945 active->clock = timestamp;
946 active->cpu = smp_processor_id();
947 active->caller = __builtin_return_address(0);
948 active->exception = exception;
949 active->level = level;
950 proceed_active_entry(id);
951 if (exception)
952 proceed_active_area(id);
953}
954
955static int debug_stoppable = 1;
956static int debug_active = 1;
957
958#define CTL_S390DBF_STOPPABLE 5678
959#define CTL_S390DBF_ACTIVE 5679
960
961/*
962 * proc handler for the running debug_active sysctl
963 * always allow read, allow write only if debug_stoppable is set or
964 * if debug_active is already off
965 */
966static int s390dbf_procactive(const struct ctl_table *table, int write,
967 void *buffer, size_t *lenp, loff_t *ppos)
968{
969 if (!write || debug_stoppable || !debug_active)
970 return proc_dointvec(table, write, buffer, lenp, ppos);
971 else
972 return 0;
973}
974
975static struct ctl_table s390dbf_table[] = {
976 {
977 .procname = "debug_stoppable",
978 .data = &debug_stoppable,
979 .maxlen = sizeof(int),
980 .mode = S_IRUGO | S_IWUSR,
981 .proc_handler = proc_dointvec,
982 },
983 {
984 .procname = "debug_active",
985 .data = &debug_active,
986 .maxlen = sizeof(int),
987 .mode = S_IRUGO | S_IWUSR,
988 .proc_handler = s390dbf_procactive,
989 },
990};
991
992static struct ctl_table_header *s390dbf_sysctl_header;
993
994/**
995 * debug_stop_all() - stops the debug feature if stopping is allowed.
996 *
997 * Return:
998 * - none
999 *
1000 * Currently used in case of a kernel oops.
1001 */
1002void debug_stop_all(void)
1003{
1004 if (debug_stoppable)
1005 debug_active = 0;
1006}
1007EXPORT_SYMBOL(debug_stop_all);
1008
1009/**
1010 * debug_set_critical() - event/exception functions try lock instead of spin.
1011 *
1012 * Return:
1013 * - none
1014 *
1015 * Currently used in case of stopping all CPUs but the current one.
1016 * Once in this state, functions to write a debug entry for an
1017 * event or exception no longer spin on the debug area lock,
1018 * but only try to get it and fail if they do not get the lock.
1019 */
1020void debug_set_critical(void)
1021{
1022 debug_critical = 1;
1023}
1024
1025/*
1026 * debug_event_common:
1027 * - write debug entry with given size
1028 */
1029debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
1030 int len)
1031{
1032 debug_entry_t *active;
1033 unsigned long flags;
1034
1035 if (!debug_active || !id->areas)
1036 return NULL;
1037 if (debug_critical) {
1038 if (!spin_trylock_irqsave(&id->lock, flags))
1039 return NULL;
1040 } else {
1041 spin_lock_irqsave(&id->lock, flags);
1042 }
1043 do {
1044 active = get_active_entry(id);
1045 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1046 if (len < id->buf_size)
1047 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1048 debug_finish_entry(id, active, level, 0);
1049 len -= id->buf_size;
1050 buf += id->buf_size;
1051 } while (len > 0);
1052
1053 spin_unlock_irqrestore(&id->lock, flags);
1054 return active;
1055}
1056EXPORT_SYMBOL(debug_event_common);
1057
1058/*
1059 * debug_exception_common:
1060 * - write debug entry with given size and switch to next debug area
1061 */
1062debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1063 const void *buf, int len)
1064{
1065 debug_entry_t *active;
1066 unsigned long flags;
1067
1068 if (!debug_active || !id->areas)
1069 return NULL;
1070 if (debug_critical) {
1071 if (!spin_trylock_irqsave(&id->lock, flags))
1072 return NULL;
1073 } else {
1074 spin_lock_irqsave(&id->lock, flags);
1075 }
1076 do {
1077 active = get_active_entry(id);
1078 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1079 if (len < id->buf_size)
1080 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1081 debug_finish_entry(id, active, level, len <= id->buf_size);
1082 len -= id->buf_size;
1083 buf += id->buf_size;
1084 } while (len > 0);
1085
1086 spin_unlock_irqrestore(&id->lock, flags);
1087 return active;
1088}
1089EXPORT_SYMBOL(debug_exception_common);
1090
1091/*
1092 * counts arguments in format string for sprintf view
1093 */
1094static inline int debug_count_numargs(char *string)
1095{
1096 int numargs = 0;
1097
1098 while (*string) {
1099 if (*string++ == '%')
1100 numargs++;
1101 }
1102 return numargs;
1103}
1104
1105/*
1106 * debug_sprintf_event:
1107 */
1108debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1109{
1110 debug_sprintf_entry_t *curr_event;
1111 debug_entry_t *active;
1112 unsigned long flags;
1113 int numargs, idx;
1114 va_list ap;
1115
1116 if (!debug_active || !id->areas)
1117 return NULL;
1118 numargs = debug_count_numargs(string);
1119
1120 if (debug_critical) {
1121 if (!spin_trylock_irqsave(&id->lock, flags))
1122 return NULL;
1123 } else {
1124 spin_lock_irqsave(&id->lock, flags);
1125 }
1126 active = get_active_entry(id);
1127 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1128 va_start(ap, string);
1129 curr_event->string = string;
1130 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1131 curr_event->args[idx] = va_arg(ap, long);
1132 va_end(ap);
1133 debug_finish_entry(id, active, level, 0);
1134 spin_unlock_irqrestore(&id->lock, flags);
1135
1136 return active;
1137}
1138EXPORT_SYMBOL(__debug_sprintf_event);
1139
1140/*
1141 * debug_sprintf_exception:
1142 */
1143debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1144{
1145 debug_sprintf_entry_t *curr_event;
1146 debug_entry_t *active;
1147 unsigned long flags;
1148 int numargs, idx;
1149 va_list ap;
1150
1151 if (!debug_active || !id->areas)
1152 return NULL;
1153
1154 numargs = debug_count_numargs(string);
1155
1156 if (debug_critical) {
1157 if (!spin_trylock_irqsave(&id->lock, flags))
1158 return NULL;
1159 } else {
1160 spin_lock_irqsave(&id->lock, flags);
1161 }
1162 active = get_active_entry(id);
1163 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1164 va_start(ap, string);
1165 curr_event->string = string;
1166 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1167 curr_event->args[idx] = va_arg(ap, long);
1168 va_end(ap);
1169 debug_finish_entry(id, active, level, 1);
1170 spin_unlock_irqrestore(&id->lock, flags);
1171
1172 return active;
1173}
1174EXPORT_SYMBOL(__debug_sprintf_exception);
1175
1176/**
1177 * debug_register_view() - registers new debug view and creates debugfs
1178 * dir entry
1179 *
1180 * @id: handle for debug log
1181 * @view: pointer to debug view struct
1182 *
1183 * Return:
1184 * - 0 : ok
1185 * - < 0: Error
1186 */
1187int debug_register_view(debug_info_t *id, struct debug_view *view)
1188{
1189 unsigned long flags;
1190 struct dentry *pde;
1191 umode_t mode;
1192 int rc = 0;
1193 int i;
1194
1195 if (!id)
1196 goto out;
1197 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1198 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1199 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1200 if (!view->input_proc)
1201 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1202 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1203 id, &debug_file_ops);
1204 spin_lock_irqsave(&id->lock, flags);
1205 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1206 if (!id->views[i])
1207 break;
1208 }
1209 if (i == DEBUG_MAX_VIEWS) {
1210 rc = -1;
1211 } else {
1212 id->views[i] = view;
1213 id->debugfs_entries[i] = pde;
1214 }
1215 spin_unlock_irqrestore(&id->lock, flags);
1216 if (rc) {
1217 pr_err("Registering view %s/%s would exceed the maximum "
1218 "number of views %i\n", id->name, view->name, i);
1219 debugfs_remove(pde);
1220 }
1221out:
1222 return rc;
1223}
1224EXPORT_SYMBOL(debug_register_view);
1225
1226/**
1227 * debug_unregister_view() - unregisters debug view and removes debugfs
1228 * dir entry
1229 *
1230 * @id: handle for debug log
1231 * @view: pointer to debug view struct
1232 *
1233 * Return:
1234 * - 0 : ok
1235 * - < 0: Error
1236 */
1237int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1238{
1239 struct dentry *dentry = NULL;
1240 unsigned long flags;
1241 int i, rc = 0;
1242
1243 if (!id)
1244 goto out;
1245 spin_lock_irqsave(&id->lock, flags);
1246 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1247 if (id->views[i] == view)
1248 break;
1249 }
1250 if (i == DEBUG_MAX_VIEWS) {
1251 rc = -1;
1252 } else {
1253 dentry = id->debugfs_entries[i];
1254 id->views[i] = NULL;
1255 id->debugfs_entries[i] = NULL;
1256 }
1257 spin_unlock_irqrestore(&id->lock, flags);
1258 debugfs_remove(dentry);
1259out:
1260 return rc;
1261}
1262EXPORT_SYMBOL(debug_unregister_view);
1263
1264static inline char *debug_get_user_string(const char __user *user_buf,
1265 size_t user_len)
1266{
1267 char *buffer;
1268
1269 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1270 if (!buffer)
1271 return ERR_PTR(-ENOMEM);
1272 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1273 kfree(buffer);
1274 return ERR_PTR(-EFAULT);
1275 }
1276 /* got the string, now strip linefeed. */
1277 if (buffer[user_len - 1] == '\n')
1278 buffer[user_len - 1] = 0;
1279 else
1280 buffer[user_len] = 0;
1281 return buffer;
1282}
1283
1284static inline int debug_get_uint(char *buf)
1285{
1286 int rc;
1287
1288 buf = skip_spaces(buf);
1289 rc = simple_strtoul(buf, &buf, 10);
1290 if (*buf)
1291 rc = -EINVAL;
1292 return rc;
1293}
1294
1295/*
1296 * functions for debug-views
1297 ***********************************
1298*/
1299
1300/*
1301 * prints out actual debug level
1302 */
1303
1304static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1305 char *out_buf, size_t out_buf_size)
1306{
1307 return scnprintf(out_buf, out_buf_size, "%i\n", id->pages_per_area);
1308}
1309
1310/*
1311 * reads new size (number of pages per debug area)
1312 */
1313
1314static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1315 struct file *file, const char __user *user_buf,
1316 size_t user_len, loff_t *offset)
1317{
1318 int rc, new_pages;
1319 char *str;
1320
1321 if (user_len > 0x10000)
1322 user_len = 0x10000;
1323 if (*offset != 0) {
1324 rc = -EPIPE;
1325 goto out;
1326 }
1327 str = debug_get_user_string(user_buf, user_len);
1328 if (IS_ERR(str)) {
1329 rc = PTR_ERR(str);
1330 goto out;
1331 }
1332 new_pages = debug_get_uint(str);
1333 if (new_pages < 0) {
1334 rc = -EINVAL;
1335 goto free_str;
1336 }
1337 rc = debug_set_size(id, id->nr_areas, new_pages);
1338 if (rc != 0) {
1339 rc = -EINVAL;
1340 goto free_str;
1341 }
1342 rc = user_len;
1343free_str:
1344 kfree(str);
1345out:
1346 *offset += user_len;
1347 return rc; /* number of input characters */
1348}
1349
1350/*
1351 * prints out actual debug level
1352 */
1353static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1354 char *out_buf, size_t out_buf_size)
1355{
1356 int rc = 0;
1357
1358 if (id->level == DEBUG_OFF_LEVEL)
1359 rc = scnprintf(out_buf, out_buf_size, "-\n");
1360 else
1361 rc = scnprintf(out_buf, out_buf_size, "%i\n", id->level);
1362 return rc;
1363}
1364
1365/*
1366 * reads new debug level
1367 */
1368static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1369 struct file *file, const char __user *user_buf,
1370 size_t user_len, loff_t *offset)
1371{
1372 int rc, new_level;
1373 char *str;
1374
1375 if (user_len > 0x10000)
1376 user_len = 0x10000;
1377 if (*offset != 0) {
1378 rc = -EPIPE;
1379 goto out;
1380 }
1381 str = debug_get_user_string(user_buf, user_len);
1382 if (IS_ERR(str)) {
1383 rc = PTR_ERR(str);
1384 goto out;
1385 }
1386 if (str[0] == '-') {
1387 debug_set_level(id, DEBUG_OFF_LEVEL);
1388 rc = user_len;
1389 goto free_str;
1390 } else {
1391 new_level = debug_get_uint(str);
1392 }
1393 if (new_level < 0) {
1394 pr_warn("%s is not a valid level for a debug feature\n", str);
1395 rc = -EINVAL;
1396 } else {
1397 debug_set_level(id, new_level);
1398 rc = user_len;
1399 }
1400free_str:
1401 kfree(str);
1402out:
1403 *offset += user_len;
1404 return rc; /* number of input characters */
1405}
1406
1407/*
1408 * flushes debug areas
1409 */
1410static void debug_flush(debug_info_t *id, int area)
1411{
1412 unsigned long flags;
1413 int i, j;
1414
1415 if (!id || !id->areas)
1416 return;
1417 spin_lock_irqsave(&id->lock, flags);
1418 if (area == DEBUG_FLUSH_ALL) {
1419 id->active_area = 0;
1420 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1421 for (i = 0; i < id->nr_areas; i++) {
1422 id->active_pages[i] = 0;
1423 for (j = 0; j < id->pages_per_area; j++)
1424 memset(id->areas[i][j], 0, PAGE_SIZE);
1425 }
1426 } else if (area >= 0 && area < id->nr_areas) {
1427 id->active_entries[area] = 0;
1428 id->active_pages[area] = 0;
1429 for (i = 0; i < id->pages_per_area; i++)
1430 memset(id->areas[area][i], 0, PAGE_SIZE);
1431 }
1432 spin_unlock_irqrestore(&id->lock, flags);
1433}
1434
1435/*
1436 * view function: flushes debug areas
1437 */
1438static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1439 struct file *file, const char __user *user_buf,
1440 size_t user_len, loff_t *offset)
1441{
1442 char input_buf[1];
1443 int rc = user_len;
1444
1445 if (user_len > 0x10000)
1446 user_len = 0x10000;
1447 if (*offset != 0) {
1448 rc = -EPIPE;
1449 goto out;
1450 }
1451 if (copy_from_user(input_buf, user_buf, 1)) {
1452 rc = -EFAULT;
1453 goto out;
1454 }
1455 if (input_buf[0] == '-') {
1456 debug_flush(id, DEBUG_FLUSH_ALL);
1457 goto out;
1458 }
1459 if (isdigit(input_buf[0])) {
1460 int area = ((int) input_buf[0] - (int) '0');
1461
1462 debug_flush(id, area);
1463 goto out;
1464 }
1465
1466 pr_info("Flushing debug data failed because %c is not a valid "
1467 "area\n", input_buf[0]);
1468
1469out:
1470 *offset += user_len;
1471 return rc; /* number of input characters */
1472}
1473
1474/*
1475 * prints debug data in hex/ascii format
1476 */
1477static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1478 char *out_buf, size_t out_buf_size, const char *in_buf)
1479{
1480 int i, rc = 0;
1481
1482 for (i = 0; i < id->buf_size; i++) {
1483 rc += scnprintf(out_buf + rc, out_buf_size - rc,
1484 "%02x ", ((unsigned char *)in_buf)[i]);
1485 }
1486 rc += scnprintf(out_buf + rc, out_buf_size - rc, "| ");
1487 for (i = 0; i < id->buf_size; i++) {
1488 unsigned char c = in_buf[i];
1489
1490 if (isascii(c) && isprint(c))
1491 rc += scnprintf(out_buf + rc, out_buf_size - rc, "%c", c);
1492 else
1493 rc += scnprintf(out_buf + rc, out_buf_size - rc, ".");
1494 }
1495 rc += scnprintf(out_buf + rc, out_buf_size - rc, "\n");
1496 return rc;
1497}
1498
1499/*
1500 * prints header for debug entry
1501 */
1502int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1503 int area, debug_entry_t *entry, char *out_buf,
1504 size_t out_buf_size)
1505{
1506 unsigned long sec, usec;
1507 unsigned long caller;
1508 unsigned int level;
1509 char *except_str;
1510 int rc = 0;
1511
1512 level = entry->level;
1513 sec = entry->clock;
1514 usec = do_div(sec, USEC_PER_SEC);
1515
1516 if (entry->exception)
1517 except_str = "*";
1518 else
1519 except_str = "-";
1520 caller = (unsigned long) entry->caller;
1521 rc += scnprintf(out_buf, out_buf_size, "%02i %011ld:%06lu %1u %1s %04u %px ",
1522 area, sec, usec, level, except_str,
1523 entry->cpu, (void *)caller);
1524 return rc;
1525}
1526EXPORT_SYMBOL(debug_dflt_header_fn);
1527
1528/*
1529 * prints debug data sprintf-formatted:
1530 * debug_sprinf_event/exception calls must be used together with this view
1531 */
1532
1533#define DEBUG_SPRINTF_MAX_ARGS 10
1534
1535static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1536 char *out_buf, size_t out_buf_size, const char *inbuf)
1537{
1538 debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
1539 int num_longs, num_used_args = 0, i, rc = 0;
1540 int index[DEBUG_SPRINTF_MAX_ARGS];
1541
1542 /* count of longs fit into one entry */
1543 num_longs = id->buf_size / sizeof(long);
1544
1545 if (num_longs < 1)
1546 goto out; /* bufsize of entry too small */
1547 if (num_longs == 1) {
1548 /* no args, we use only the string */
1549 rc = strscpy(out_buf, curr_event->string, out_buf_size);
1550 if (rc == -E2BIG)
1551 rc = out_buf_size;
1552 goto out;
1553 }
1554
1555 /* number of arguments used for sprintf (without the format string) */
1556 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1557
1558 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1559
1560 for (i = 0; i < num_used_args; i++)
1561 index[i] = i;
1562
1563 rc = scnprintf(out_buf, out_buf_size,
1564 curr_event->string, curr_event->args[index[0]],
1565 curr_event->args[index[1]], curr_event->args[index[2]],
1566 curr_event->args[index[3]], curr_event->args[index[4]],
1567 curr_event->args[index[5]], curr_event->args[index[6]],
1568 curr_event->args[index[7]], curr_event->args[index[8]],
1569 curr_event->args[index[9]]);
1570out:
1571 return rc;
1572}
1573
1574/*
1575 * debug_init:
1576 * - is called exactly once to initialize the debug feature
1577 */
1578static int __init debug_init(void)
1579{
1580 s390dbf_sysctl_header = register_sysctl("s390dbf", s390dbf_table);
1581 mutex_lock(&debug_mutex);
1582 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1583 initialized = 1;
1584 mutex_unlock(&debug_mutex);
1585 return 0;
1586}
1587postcore_initcall(debug_init);